Show HN: We built a Plug-in Home Battery for the 99.7% of us without Powerwalls (pilaenergy.com)
Pila (https://pila.energy/) is a home battery that plugs into a standard wall outlet, provides smart backup power, energy shifting, and grid services. It’s more than a power bank—it’s a distributed energy system that can scale across multiple rooms, entire buildings, and work together in real time as a coordinated system. We built Pila to be local first with an open API to allow developers to build use cases on top of our hardware (Home Assistant, etc).
Big batteries like Tesla Powerwall and Enphase are great if you own a home and can afford a $10K+ electrical project, but they require permanent installation, electricians, and panel upgrades—which makes them inaccessible for renters, apartments, and cost-conscious homeowners. Over 50% of the cost of installing a Powerwall isn’t even the battery itself—it’s soft costs: labor, permitting, etc. We wanted to create an entry point for more people to access energy security at home.
How does it work?
Plug Pila into any 120V wall outlet, and power passes through to connected devices and appliances. The inverter, LFP battery, BMS, grid disconnection, controller, and wireless connectivity are all built in. (details at https://pila.energy/tech-specs)
When an outage happens, the onboard inverter detects the power loss within 20ms and automatically disconnects from the grid (islanding). Whether you’re home or away, backup kicks in instantly. A built-in cellular radio ensures you get a notification even if your home WiFi is out. Pila is 1.6kWh. That will backup a standard fridge for over a day.
One key challenge we faced with a distributed architecture was coordination between batteries, for things like solar-following and managing real-time draw from your utility connection. Unlike large garage systems, where you can run a wired CAN bus, our batteries are spread across the home. We’re solving this with a sub-GHz wireless mesh network—self-healing, coordinator-less, and designed to make setup and expansion as simple as plugging in another unit.
Long-term, we’d love to open up this protocol to provide a more reliable communication layer for energy products in noisy built environments—reducing reliance on consumer Wi-Fi.
We want to deliver the value you’d expect from a whole-home battery like Powerwall, in a plug-in format. That means going beyond a basic lead acid UPS with real home energy management, useful insights about power use, power larger loads like sump pumps, and even deliver grid services.
Most portable batteries are missing the functionality that makes a home battery useful: no bidirectional power, no integration with solar or smart home systems, and no ability to manage home energy dynamically. They tend to be boxy, ruggedized, meant to be moved around, not seamlessly integrated into your living space. On top of that, many use e-mobility battery chemistries, which are great for delivering high power on demand but wear out faster when cycled daily for home energy use.
As a renter myself, I started Pila because these awesome energy products aren’t accessible enough. And frankly, generators are loud, expensive, and a pain to deal with. Even many Powerwall owners I’ve talked to say they really care about keeping the fridge, WiFi, and a sump pump running—so why does energy resilience have to be so complicated and expensive?
As the grid struggles to keep up with demand, we believe modular, renter-friendly batteries can make home energy resilience more accessible.
What's been your ...
491 comments
[ 4.2 ms ] story [ 54.7 ms ] threadHow long will this keep a fridge powered?
I guess you could flip the trip switch to isolate the circuit?
The bigger issue is how many amps the heating system draws. Assuming it's really a furnace that pumps hot water, (as opposed to a boiler that sends steam to radiators) those pumps really do draw a lot of current.
> When an outage happens, the onboard inverter detects the power loss within 20ms and automatically disconnects from the grid (islanding)
How does this work? Do I need to install anything additional in my grid? Like, how does the fridge "know" that it should now draw power from Pila?
Sorry for my noob questions :D
My one question would be: does it work with home assistant? It would be great to integrate in te energy dashboard.
As an important caveat on solar: if I'm reading correctly, it appears that the main unit only has support for a small amount of solar input directly connected to it (100 W, which makes me suspect it may be using USB PD for input), while larger amounts need the expansion pack, or a separately installed system.
My well pump is 120V, but I don't keep it in my house. It's in a shed out back built over the well and tank. The shed is not insulated, but does have a 400W space heater plugged into one of these [1] that tries to keep it above freezing in there. I think most of the time it succeeds but it is possible that for a few days a year it might get below freezing for a while.
I have no idea what the humidity is like, or how hot it can get in the summer.
Would the current Pila be OK in that kind of environment?
[1] https://www.amazon.com/Farm-Innovators-TC-3-Thermostatically...
I’ve had ten power outages in the past six months, one mile from an international airport. I’ve lived through hundreds hours of power outages due to PG&E’s fucking incompetence in the past ten years. You’ll have to judge for yourself whether that justifies my comment - but, if you were a startup considering a 240V outlet on your home battery solution, I’m pointing out an entire category of uses that they may not have considered:
US kitchen countertop equipment that runs at higher power draw when a 240 outlet is available.
As an apartment renter, I have no reasonable solution today for a battery that can cope with my kitchen at all, prior to this one — and if they go 240V, I can upgrade my kitchen appliances, take them with me when I move, and be more resilient to power outages. And if that puts more weight behind the 240V purpose so they eventually offer a model for people’s furnaces, cool beans. I may not be able to convince my landlord to install a Charlie range, but I already have battery backups in every room except my kitchen, so there’s an unmet need that this startup’s a very close fit for already.
Being dismissive about someone’s questions will cause you to overlook potential market niches that have no viable solutions today. Your competitors thank you for your service :)
That should mean there are UPSs already available, although possibly they don't come in small sizes.
Any timeline yet for international distribution?
Parts of Pila's power electronics are already 230~240V capable. We've just launched in the US, and are doing our best to stay focused on excellent support for our home market before expanding. That said, I could see 2026 being the right time for expansion... stay tuned mate!
When you say it is bidirectional, what does that mean? It sounds like it means backfeeding into the wall outlet, but I dont think that can be right.
I am also missing how this is different from other inline device battery backups that have been around for decades and cost 20% the price. Is it that it has a built in DC charge controller for an optional solar panel?
Overall, This seems like a tough space to carve out a niche. It seems like the product is trying to position between whole house batteries ( powerwall), multi-purpose power stations (ecoflow), and generic outlet battery backups. As an outside observer reading your website, it wasnt immediately obvious how this solution is better than any of those in their respective domain, or how its own domain is different.
Edit: Maybe I misunderstand the solar charging? How does this work? Does it charge from AC outlet during solar production? Is this managed with a timer, or other smart connections to the solar inverter, ect?
On bidirectionality: Yep this would involve backfeeding an outlet - It's new here in the U.S. but not unprecedented. Plug-in "Balcony Solar" systems have taken Germany by storm in recent years, and Utah just passed the first bill in the US (HB340) to allow plug-in solar panels to export to the grid. Pretty cool to see new these options emerge for renters. There's still work to do to take this to mainstream and get all jurisdictions, utilities, and equipment manufacturers aligned on final standards but I'm optimistic.
On solar: You've got 2 options -- Timed charging with a rooftop system just like how "AC-coupled" batteries like Powerwall work. Or, "DC-coupling" by connecting solar PV panels directly to Pila. If Pila is in your kitchen, running a DC-coupled panel wire may only be practical in a multi-day outage, but for a fridge in the garage it's a relatively easy option.
On differentiation: We're up for the challenge :) - With Powerwall and SPAN (or other home devices like Nest) my take is it's the software and integration value that sets them out ahead. That's where we're really excited to create value and carve our niche. But zooming out, it's a big market, and our goal is to give folks more options to fit their needs, and it's totally going to be the case that simpler portable camping batteries are right for some, and big Powerwall-like batteries are right for others.
Portable camping batteries, generally: More options come out every year, but on the hardware side they're not optimal since most use e-mobility battery chemistries, which are great for delivering high power on demand but wear out fast when cycled daily for home energy use. And since they’re meant to be manually deployed, they’re not always charged and ready when you actually need them—unlike a system that’s always on, managing power in the background without you having to think about it.
Great work on the local API first approach. I can't remember the last SmartAppTM device that was local API first and not wholely dependent on some fly-by-night SaaS that requires you to sign-up. Hope we see more of this in the industry. Span is infamous for removing local API control of their panels.
Are you planning to charge a monthly fee? I’d be open to that, but it would be nice to not pay for more than the hardware. I.e. build the operating costs into the cost of the initial purchase
This thing is way too "nice" and polished for its relatively low price tag, meaning it's likely being significantly subsidized by investors, who will eventually want a return on their investment and all these promises will go out the window.
I already use an Ecoflow as quasi-UPS in my networking closet and one for a chest freezer and its worked great for that. They advertise a ~25ms switch over. I think (could be wrong) they also have features like scheduled tasks to managed recharge/discharge schedules.
Is the main difference between an Ecoflow and this basically the form factor?
The form factor and the potential rugpull in the future when this turns into a subscription and/or a "virtual power plant" where you get the homeowners to pay for the device while the manufacturers sells the aggregated capacity to source/sink power to the highest bidder and keeps the profits. There's a reason these have built-in cellular; you don't put that in (and pay the ongoing data charges) without one.
This thing is too "nice" and polished for its price point, so profits will have to come from somewhere down the line (because they're definitely not making any on the actual device sales).
During a recent major weather event outage, a neighbor up the street was running a generator, that I think was not properly islanded. I experienced it by having some devices making weird sounds because they were receiving some low level voltage. They were probably leaking to tens of neighbors and losing generator output in the process.
Do your batteries need any kind of an internet connection to set up or operate? Assuming I wouldn't want to use the app.
It has a 20 ms switch-over to battery backup. APC UPS' range from 2 - 6 ms.
There is a StackOverflow answer that says the upper limit for servers is 25 ms but 20 ms might be cutting it fine.
https://serverfault.com/questions/564156/what-is-the-interru...
I couldn't find a price on the website (the $99 is just for a reservation) but from this thread it looks like it's priced at $1k [1].
For context, in the USA, 30 KWh is a rough estimate for average daily home usage [2].
[0] https://pilaenergy.com/tech-specs#faq
[1] https://news.ycombinator.com/item?id=43333996
[2] https://www.eia.gov/energyexplained/use-of-energy/electricit...
Also, spot on that the average home draws about 30kWh, and with an EV driven average daily ranges that'll jump to about 60kWh.
Before starting to apply voltage to a home electric gird, I guess you need to disconnect it from the central grid - how do you do that? Or do you detect when the grid goes down and comes back up?
This makes the LCD displays on the front page of the website listing "5 days 6 h ours" and similar on a single unit very misleading. That amount of backup would cost $128,000.
The pre-order page says it will be $1300 after the pre-order period.
This is meant as a more precise, room-by-room backup solution!
Maybe I’m wrong though, just wanted to position.
Also, FWIW, it appears your web page pricing is slightly cheaper per kWh than the Lion, so good on you.
Right on! It’s a great product and insane value for all the features it provides.
Based on experiments like https://www.youtube.com/watch?v=jtNq-0kV8YM, I'm extremely skeptical. Can you back this claim?
Also, why are people going to spend $1,300 on this when a good UPS is a fraction of the price, and (for example) an Anker SOLIX F3800 Plus is $3,200?
The win for me is the form factor. It can slot right next to any appliance or utility room shelf. The cost is not bad by comparison to portable battery systems, but portable battery systems fall into two form factors:
1. Garage / basement stacks that have to connect to a generator hook-up: which itself costs kilo-dollars. And what if my garage / utility panel isn't heated? Extreme temp swings can degrade these I'd imagine.
2) carry or roll-away. Which is great for camping or pulling out of the closet during an outage, but that's not convenient and not what I'm looking for
And finally, the UPS-like standby power beats both options as well. The solar generator types don't do passthrough power well (they warn against it) and the garage/basement stacks have to be connected to a cutover switch anyway.
Correct me if I'm wrong nowadays but this product beats both those for these reasons.
Batteries can provide significant savings but for that you need to actually use them fully, either by load-shifting significant loads (if you have enough to fully consume the battery capacity), or just charging/discharging the battery directly into the grid (essentially acting like a grid storage system - charging the battery to full when energy is the cheapest, and dumping it back when it's the most profitable). Even better when you have solar - instead of selling that energy at low feed-in prices, save it in batteries and use it once the sun goes down so (if you have enough battery capacity) you never ever need to actually "buy" any energy from the grid.
I believe the Pila can technically do the above, although its battery capacity is probably too small to ever recoup its purchase price on this type of arbitrage. However, the underlying concept is absolutely workable and profitable with the right equipment.
That's my point, thank you for putting it so succinctly. The front page opens showing the Pila being used for a refrigerator — presumably doing load shifting, given the front page marketing copy I quoted — so I think asking for data showing that this is a legitimate use case is fair.
The other thing is that rewiring a main panel for generator and/or solar to provide emergency power to a subset of circuits is preferred to simply trying to power everything with a tiny battery pack. This usually means adding a subpanel and an automatic transfer switch, which is a heck of a lot simpler than running extension cords through the house and much more fine-grained than powering everything with backfeed.
How many people regularly experience power outages (ok, if you're American relying on Canadian electricity, you might have a right to be concerned).
I'm surprised you're not touting the "save on your power bill" benefits. Could this not store power when rates are low, and use the battery when rates are higher, while maintaining a balanced minimum storage amount to ensure power is available should the power go out?
I'd think it could be quite smart about this if you looked at weather patterns and other factors to calculate a likelihood of an outage, and ensured more back-up was available.
From a selling stand-point, isn't saving money every day a better feature than "just in case the electricity goes out"?
You don't have to go that far. Puerto Rico is a United States territory with a third-world tier power grid. Most Puerto Ricans rely on electric generators and battery backup systems to survive their day-to-day.
https://www.npr.org/2024/12/31/nx-s1-5243984/puerto-rico-pow...
This is bordering a humanitarian crisis and I'm surprised it gets little attention in the mainland. These outages have a real human cost: the elderly struggle with maintaining their generators. Hospitals rely on generators. Roads and sidewalks are in the dark. The haves get diesel delivered; the have-nots struggle. Some, especially the elderly, die in fires or asphyxia due to their constant operation.
https://www.univision.com/local/puerto-rico-wlii/hombre-muer...
https://www.primerahora.com/noticias/policia-tribunales/nota...
A woman died on New Year's Eve due to a fire in her residence while trying to operate a transfer switch. The power was out all night across the island.
https://wapa.tv/noticias/locales/falla-en-planta-el-ctrica-p...
Apologies for derailing, but it bothers me how little attention this gets. The privatized power company has successfully externalized its costs--thousands of Puerto Ricans are going into debt to install solar panels. Half of the island lives under the poverty line.
People are desperate. A year ago, the Dept of Energy established federal incentives for solar panel installations in the island. These were the kilometric lines to get a voucher:
https://www.telemundopr.com/noticias/puerto-rico/cientos-de-...
In short:
a) This is a real problem. Puerto Rico has 3.5 million American citizens, more than some states.
b) Battery backup systems, solar panel installations and generators are a necessity in these areas.
I wish this product was targeted towards lower income families, but any innovation in the space is welcome.
- Power instability causes serious economic damage to individuals, families and small businesses. Imagine establishing a business in an island where you don't know if you'll have power today.
- In PR, you don't buy groceries for an entire month. The power goes out once and all your food is ruined. Families bear the brunt of these reliability failures.
- Outages damage your appliances. This is even more economic damage to families and the poor. A couple years ago, in jest, protesters from across the island took their damaged appliances to the power company headquarters and dropped them off there.
- Diabetics have to use generators or special machines to keep their insulin refrigerated.
I could keep going. It's a shame that this absurdity is happening in the wealthiest country in the world.
Until then, I don't see any hope of meaningful federal support in times of Puerto Rican crisis. Too many Americans are not sure whether Hawaii is a state, or if Rhode Island is an island. The amount of time that PR occupies anyone's thoughts in Real America™ is basically nil. Just like Trinidad, or Turks and Caicos. "Oh, I know someone who took a cruise there. They don't speak English do they?" That's it.
† I also support Puerto Rican self-determination and independence. :) But that path will not bring FEMA, or infrastructure investment.
Anecdotally in a major city it was rare I would not have a power outage several times a year. In a more rural location now, it's rare I have a month without a power outage, some very extended.
We have a backup generator and it has saved our frozen foods at least a dozen times over the last few years. Installing a backup generator costs about $10k for a whole house permanently installed unit, so it's not a small cost, and the running and maintenance costs are not zero ($5 an hour when running, $100+ a year for parts and consumables)
Does your generator require maintenance? Is it loud?
It does, and it is, but those are not super major factors.
I expect to save my pennies and do a whole house LiFePO4 bank at some point
At ~$600/kWh for capacity, the ROI isn't great. I have a pretty big differential on my rates because I have an EV, and even then I'd need over a decade to make the $1,000 back assuming I fully discharged it every day.
1. Have you considered building a “microgrid interconnection device” to go with this to allow the batteries to backfeed a house in the event of an outage? (This would require native 240V split-phase capability and/or an auto-transformer.)
2. Have you considered removing the fade-in-when-scrolling abomination on your website?
2. Feedback taken hah
DER = Distributed Energy Resource ?
SPAN = an energy device company https://www.span.io/ ?
Just had to check the definition of some acronyms and thought others might find the results helpful inline.
I suppose another potential issue would be exceeding the capacity of a panel bus. Balcony solar has the same problem, and I guess no one os likely to connect enough balcony solar units to cause a real problem.
- Some services cannot be switched at the meter ring. This includes services that use a current transformer separate from the meter. (As far as I know, this includes all services over “Class 320”.)
- Some apartments aren’t separately metered. Fortunately, this is rare.
- Some users will want to back up only part of a service.
How does that work? Is just not putting energy out the input "plug" count as a MID?
When utility power drops, Pila & Powerwall react exactly the same. They both detect the outage, open the MID, and power load downstream of the MID. In the case of Pila it powers loads downstream / plugged into Pila.
In addition to that you're feeding energy back in through a much smaller wire so you're limited to the capability of the circuit it's connected to and the devices have to be smart enough to actually limit their output to what the wall can handle. Otherwise imagine you have 2 of these each on 1000W circuits (not a normal circuit but for convenience lets pretend) and you have 1500W of load running elsewhere in the house. One runs out of power because it had a lower charge state when power failed, now unless the remaining UPS limits it's output and browns out everything you're pulling 150% the rated power of your circuit, potentially damaging the wires or the loads you're powering.
This is potentially what's causing fires on nVidia's high power connectors, one connection wears out or is simply loose so more power flows through the remaining pins and it's too much for those wires causing fires/melting the wires.
Technically possible, irresponsible, bad advice, and probably won’t work in most scenarios.
First the smaller circuits will trip first, that's where the current is actually flowing, there wouldn't be any actually flowing through the whole house breaker in your idea. The main circuit to your house is 100+ Amps (this would be a tiny old circuit most houses have larger main feeds these days) at least. You'd have to feed at that much through the main disconnect for it to trip.
Second even if you could push that many amps through the main breaker somehow to trip it you'd be feeding it through wires designed for 15-20 amp nominal loads which would cook them.
Well, you'd end up tripping the 15-20 amp breaker protecting those wires first.
The fault current that a breaker is required to be able to interrupt is two orders of magnitude larger than we're talking about feeding into the wire, and a 15 amp breaker is designed to _not_ interrupt a 150 amp load until a second has passed (there's a rating curve for this): some loads might require that much current briefly, and the wire in the wall is not going to overheat in that time (that's why the breaker has the curve that it does: to model and therefore protect the allowable heating of the wiring).
Doubly so because it doesn't even do what we want it to which would be to switch the main breaker off.